1. Field of the Invention
The invention relates to an apparatus for recording a first information signal with a first bit-rate and a second information signal with a second bit-rate, which is larger than the first bit-rate, to an apparatus for reproducing the first and the second information signal, and to a method for recording the first and the second information signal.
As an example, the first information signal can be in the form of an SD (standard definition) video signal and the second information signal can be in the form of an HD (high definition) video signal. The SD and HD video signal could have been incorporated into a first and a second MPEG transport stream, respectively, for recording the first and second MPEG transport streams on the record carrier. The first and second information signals can also be in the form of data signals having first and second bit-rates that could have been incorporated in first and second MPEG transport streams.
2. Description of the Related Art
An apparatus for recording an information signal in slant tracks on a record carrier is described in U.S. Pat. Nos. 5,937,137, 6,055,358 and 6,246,830 corresponding to published International Patent Application No. WO 96/06426 (PHO 94.513), documents D1 in the List Of Related Documents. The apparatus is meant to record an analog video signal in accordance with the VHS recording format on the record carrier, and is capable of recording a digital video signal on the record carrier.
An object of the invention is to provide a simplified apparatus for recording the first and second information signals in the first and second recording modes, respectively. The apparatus for recording a first information signal with a first bit-rate in a first recording mode or a second information signal with a second bit-rate in a second recording mode, so as to produce slant tracks on a magnetic record carrier, comprises:
input means for receiving the first or the second information signal,
processing means for processing the first or the second information signal so as to produce a processed first or second information signal, respectively,
writing means for writing the processed first or second information signal in said first and second recording modes, respectively, so as to produce said slant tracks, and
transporting means for transporting the record carrier with a first or a second record carrier speed in said first and second recording modes, respectively, the second record carrier speed being larger than the first record carrier speed, and the second bit-rate being higher than the first bit-rate, the processing means comprising first and second processing units and a multiplexer unit, the first processing unit being adapted to process the first information signal in said first recording mode so as to obtain said processed first information signal for recording, the multiplexer unit being adapted to multiplex the second information signal into a first signal component and a second signal component in said second recording mode, the first processing unit being adapted to process the first signal component into a processed first signal component in said second recording mode, the second processing unit being adapted to process the second signal component into a processed second signal component in said second recording mode, wherein the writing means comprises at least one pair of a first and a second write head, having azimuth angles substantially equal to +xcex1 and xe2x88x92xcex1, respectively, and at least one pair of a third and a fourth write head having azimuth angles substantially equal to +xcex2 and xe2x88x92xcex2, respectively, the writing means being adapted to write, in said first recording mode, the processed first information signal on said record carrier using said at least one pair of the first and second write heads, the writing means further being adapted to write, in said second recording mode, said processed first signal component on said record carrier using said at least one pair of the first and second write head and to write said processed second signal component on said record carrier using said at least one pair of the third and fourth write head, and wherein xcex1 and xcex2 are unequal to each other.
The invention is based on the following recognition. For recording the second information signal, a larger bit-rate is required than for recording the first information signal. A recording apparatus for recording the first information signal is thus generally not capable of recording the second information signal unless special measures are taken. One solution is to increase the record carrier transport speed and add heads to the rotating head drum. Reference is made in this respect to U.S. Pat. Nos. 5,412,515 and 5,495,369, corresponding to European Patent Application No. EP 346,973 (PHN 12.599), documents D2 in the List Of Related Documents. Further, in order to process the second information signal so as to enable recording on the record carrier, it is required to increase the clock frequency of the processing electronics. This may not always be possible.
In the further discussion, it will be assumed that the second information signal is an HD video signal that has such an information bit-rate that it requires, at maximum, a recording bit-rate which is twice the recording bit-rate for recording the first information signal. It should, however, be noted that this is not an essential requirement. The present invention offers a solution to the above problem that it is not always possible to increase the clock frequency for the processing electronics. In accordance with the invention, in the second recording mode, the incoming HD video signal is split into two separate datastreams, and each datastream is processed by a separate processing unit that is normally available for processing the SD video signal. Both processing units can now run at a clock frequency which is the same as in the first recording mode. This offers a simplified apparatus for recording both the first information signal and the second information signal.